In order to control a wide variety of troublesome broadleaf and grass weed species in the presence of cereal crops, especially in rice culture (upland and paddy), a combination application of one or more herbicides is generally required. The compound, 1-{[o-(cyclopropylcarbonyl)phenyl]sulfamoyl}-3-(4,6-dimethoxy-2-pyrimidiny l)urea is a crop-selective herbicide which is highly effective in controlling broadleaf weeds and sedges and is described in U.S. Pat. No. 5,009,699. In present day agronomic practice a number of effective grass herbicides are available which are selective in cereal crops such as dinitroaniline herbicides, thiocarbamate herbicides and chloroacetamide herbicides. However, many of these herbicides are liquids or low-melting solids and when one or more are used in combination with the above-said sulfamoyl urea to achieve broad spectrum weed control in the presence of cereal crops, the sulfamoyl urea compound may become unstable with the passage of time and lose its efficacious properties.
It is, therefore, an object of this invention to provide a stable combination herbicide composition for the control of noxious grass and broadleaf plant species and sedges which plague cereal crops, especially upland rice crops and paddy rice fields.